fs/ext4/xattr_user.c

   1 /*
   2  * linux/fs/ext4/xattr_user.c
   3  * Handler for extended user attributes.
   4  *
   5  * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/string.h>
  10 #include <linux/fs.h>
  11 #include "ext4_jbd2.h"
  12 #include "ext4.h"
  13 #include "xattr.h"
  14
  15 #define XATTR_USER_PREFIX "user."
  16
  17 static size_t
  18 ext4_xattr_user_list(struct inode *inode, char *list, size_t list_size,
  19                      const char *name, size_t name_len)
  20 {
  21         const size_t prefix_len = sizeof(XATTR_USER_PREFIX)-1;
  22         const size_t total_len = prefix_len + name_len + 1;
  23
  24         if (!test_opt(inode->i_sb, XATTR_USER))
  25                 return 0;
  26
  27         if (list && total_len <= list_size) {
  28                 memcpy(list, XATTR_USER_PREFIX, prefix_len);
  29                 memcpy(list+prefix_len, name, name_len);
  30                 list[prefix_len + name_len] = '\0';
  31         }
  32         return total_len;
  33 }
  34
  35 static int
  36 ext4_xattr_user_get(struct inode *inode, const char *name,
  37                     void *buffer, size_t size)
  38 {
  39         if (strcmp(name, "") == 0)
  40                 return -EINVAL;
  41         if (!test_opt(inode->i_sb, XATTR_USER))
  42                 return -EOPNOTSUPP;
  43         return ext4_xattr_get(inode, EXT4_XATTR_INDEX_USER, name, buffer, size);
  44 }
  45
  46 static int
  47 ext4_xattr_user_set(struct inode *inode, const char *name,
  48                     const void *value, size_t size, int flags)
  49 {
  50         if (strcmp(name, "") == 0)
  51                 return -EINVAL;
  52         if (!test_opt(inode->i_sb, XATTR_USER))
  53                 return -EOPNOTSUPP;
  54         return ext4_xattr_set(inode, EXT4_XATTR_INDEX_USER, name,
  55                               value, size, flags);
  56 }
  57
  58 struct xattr_handler ext4_xattr_user_handler = {
  59         .prefix = XATTR_USER_PREFIX,
  60         .list   = ext4_xattr_user_list,
  61         .get    = ext4_xattr_user_get,
  62         .set    = ext4_xattr_user_set,
  63 };